Supernatural x The Mortal Instruments
by YouDidn'tSeeThatComing616
Summary: Sam and Dean head to New York for a case which turns into two cases and then three. On the first two cases they meet Nephilim, children of the Angel Raziel according to Castiel. On the third case, they finally meet up properly and team up to kill a black eyed son of a bitch. Except, the demon was supposed to be an easy kill? Why are none of the blades working on it? Well... shit.


"So get this," Sam called out, his eyes scanning his laptop screen. "There have been a string of murders in New York, all of them with their blood drained."

"Oh goody," Dean was plopped down next to Sam on the couch. "I cleaned all the weapons just for them to get dirty again." Dean glanced at the bed with weapons carefully laid out on it. Just now was he sharpening them and getting the dried blood off.

"The police think that it's a serial killer taking their victims blood to sell it." Sam continued.

"Guess we got ourselves another case." Dean said as he got up and headed for the mini fridge. "Beer?" He asked Sam just as he opened one. "Oh come on, it's just a vampire. I could take it on with my eyes closed and my hands tied behind my back. Stop worrying." Dean reasoned when Sam shook his head.

"Vampires don't travel alone." Sam reminded Dean. "The group could be pretty large."

"Sam, you and I have taken down twenty vampires by ourselves." Dean looked Sam in the eye. "I think we're fine."

Sam sighed and gave in as Dean handed him a bottle. "Now," Dean began. "Let's celebrate."

"What are we even celebrating?" Sam took a gulp of his drink, already feeling a whole lot better.

"My existence." Dean said with a smug grin.

"I'm Agent Stark and he's Agent Barton." Dean smoothly lied, flashing the fake badges. "We're with the FBI, investigating the murders."

"Oh please come in." The woman said. She was quite tall and looked as if she used to be beautiful once upon a time. Her eyes were a little puffy and she had bags underneath them. Her shoulder length hair seemed unkept and dirty.

"We're here about your daughter." Dean, or Agent Stark, said.

"What can you tell us about her?" Agent Barton--Sam--spokeup.

"Sit down please." The trio sat down on the red couches. "Would you like some tea?" When the boys shook their head, the woman continued. "Leah was a nice girl. She didn't deserve any of this." Tears threatened to drop out, Dean noted, out of the woman's eyes.

"I'm very sorry, Mrs. Johnson." Sam consoled.

"She would come home from college around 7:30 at night and would leave at 7 a.m." Mrs. Johnson continued. "She really loved art. Of course, once she started college, she barely had any time for it. Sh-she used to make paintings of me and I would frame them." Tears were falling down the women's face as her voice trembled with each word.

"Is there anything you could tell us about her relationships?" Sam asked. "Or maybe she told you about someone she met a few days ago?"

"No." Mrs Johnson shook her head and blinked a few times. "She told me nothing like that."

After a few more questions, the brothers politely thanked the lady and apologised for bothering her.

"Nothing." Dean sais once they were seated in the car. "Told you there was no point. Vampires are monster who kill their prey at random."

"You're right." Sam agreed, taking of his jacket. "Next step is to find their base."

"Sammy look." Dean was pointing to a map marked with red pins at a seemingly random order. "All these are connected by one sewer line."

"So you're saying the vampires are living in the sewers?" Sam asked looking over his shoulder at the map.

"The abandoned factory over there," Dean pointed. "Has full access to that sewer line."

"Guess we know where we're going." Sam looked at his watch. "Do you wanna scope the place out? It's only 6."

Dean was already up and shrugging on his jacket. "I always wanna take down some of these bloodsucking bastards."

"Do you have the special blade Cas gave you?" Dean asked before taking his own out. Castiel had given the brothers two blades, a lot like the angel blades except those ones could kill everything except for angels.

Sam nodded and pulled his out in return. "Come on. I hear noise inside, the vampires might be arguing. It'll be a good distraction." Sam slowly advanced towards the window before breaking it.

The broken shards barely fazed Dean as he crawled over, Sam right behind him.

Dean was vaguely surprised at the two teenagers trying to fight off the seven vampires. He examined them. They didn't seem like hunters, because first of all, the were carrying a wooden stake. Everyone knew that lore was a hoax. And second of all, they had a flamethrower with them. Another hoax.

"Hey Dean." Sam interrupted his thoughts. "You take the right and I'll go left."

"Let's go hunt us some sparkling suckers." Dean said, walking in the shadows towards one of the vampires. The teenagers were trying very hard to defend themselves, but they couldn't keep this up forever.

Dean took one long stride before cutting the vampires head clean off. The other five vampires noticed him and advanced. Out of the corner of his eyes, he could see Sam heading towards him as well, after killing a bloodsucker.

Sam held three fingers up for Dean to see and began counting down. Three. Two. One. Sam and Dean lurched forward at the same time.

They swiftly fought off the five vamps through their years of experience and muscle memory. Dean slashed off another vampires head and was once again surprised at how well the blade worked.

Sam went low when Dean went high. Dean went left when Sam went right. Only working together for so long made them this way. They knew each other's moves so well, that the fight was over in just a minute.

Dean twirled his dagger and reached down before cleaning the blood off with the vampires clothes.

"Who are you?" The blond teenager scoffed as he asked the two brothers.

"I could ask you the same thing." Dean retaliated.

"So I'm guessing you know about vampires?" The dark haired boy said.

"Yeah, no shit." Dean replied. "How do you know about them?" Dean was definitely suspicious.

"Who are you?" The blonde one repeated slowly as if talking to a child who couldn't understand what he was saying.

"The people that just saved your asses." Dean said, still not giving a direct answer.

"We hunt monsters." Sam said much to Deans protests.

"A bunch of mundies that think they hunt monsters." Blondie scoffed, whispering to the other guy.

"But they did know how to kill the vampires." The other teenager reasoned.

"Are we gonna pretend like we can't hear you or…" Dean questioned but only got glared at in return.

"Hey Sam." Dean nudged him. "Do you see the strange markings over their skin. Take a picture. We can ask Cas later what they mean."

Sam slyly took out his phone and pretended to check the time when in reality he was taking multiple pictures.

"Yeah," Blondie said loudly. "How did you know how to kill it."

"We've been hunting these things since we were nine kid." Dean answered, trying to examine the weird tattoos on their bodies.

"How come it didn't flinch away from the sunlight." The black haired boy answered.

"What is this? Dracula?" Dean ridiculed. "Vampires aren't scared of sunlight."

"You kids should stay out of this. Trust me." Sam said before elbowing Dean and walking away.

"You got the pictures?" Dean whispered and Sam nodded.

"Those are runes." Castiel announced after taking one look at the pictures.

"The symbols used for language?" Sam spoke up.

"Yes." Castiel confirmed and pointed at one. "These ones are very similar to Enochian, the language of Heaven. That one means strength."

"So what exactly are they?" Dean asked. "Are they hunters who use voodoo."

Castiel looked at Dean. "They are Nephilim."

"Nephilim." Sam echoed, his voice confused. "Offsprings of an angel and human."

"Nerd." Dean muttered under his breath. Out loud he said, "Shouldn't they be more powerful. Like the ones we met before."

"No." Castiel replied. "These are a different type. Raziel, an angel of the lord, was summoned by a human in, what you humans would refer as the eleventh century. The human was called Jonathan Shadowhunter. He begged Raziel to mix his blood in a cup so that Jonathan could create a race of demon fighters. Raziel agreed for the greater good. Jonathan was then given The Mortal Instruments, three immensely powerful objects, and became a Nephilim. The Nephilim now go with the title shadowhunter because of Jonathan."

"Sam must be loving this history lesson." Dean muttered.

Sam ignored him. "So how many shadowhunters are there, and how are they so different from us?"

"There are about a thousand only, they keep on dying." Castiel answered the first question. "You hunters use guns and other weapons while the Nephilim, shadowhunters, use weapons with runes. They also have a government in a city called Idris, which is hidden from people."

"They have more resources than we do, but two "shadowhunters" couldn't even beat a bunch of sparkling mosquitos?" Dean scoffed. "Real help they are."

"Dean," Sam started. "They are teenagers."

"So?" Dean questioned. "You remember what we did when we were teenagers. Hell, you shot your first creepy crawly when you were eight. No Sam." Dean put up his hand as Sam opened his mouth. "Where were this people when we were fighting Lucifer? The fucking devil." Dean raged. "There would have been a lot less casualties if we had had some backup. Some help would have been nice in the freaking apocalypse."

"Maybe they didn't know about the apocalypse." Sam offered.

"That is likely." Castiel thought out loud. "It is possible that the creatures they fight are different from ours."

"So now what do we do?" Dean asked. "Pretend we never met them?"

"I say we talk to them. Try to find out more." Sam said. "In the future they could help us."

"So you're saying we ally ourselves with them?" Dean confirmed.

"It could help us Dean." Sam said.

"Fine." Dean sighed and gave in. "How do we find them."

"What do you think?" Alec asked Maryse.

"Wait." Clary spoke up. "So you're saying a bunch of mundies killed seven vampires on their own." She clarified.

"Yes my dear Clary." Jace answered. "Nice to see you're taking notes. Studying for the exam I see."

Alec ignored Jace. "Two mundies. Seven vampires."

"It is possible they could be shadowhunters who aren't with the clave." Maryse reasoned. "But then they should have recognised you two."

"They could see through our glamour runes. They both wouldn't have the sight at the same time, would they?" Alec piped up.

"Jace herondale and Alec Lightwood." Isabelle spoke gesturing with her hands. "Outshined by two mundanes." She ridiculed.

"In our defence, they weren't normal vampires." Alec defended. "Fire didn't affect them at all. The stake only seemed to anger them and the blades didn't work either. They also walked through sunshine without even flinching in the slightest."

Maryse gaped. "Are you sure."

"Yeah." Jace answered. "One of the mundies even looked at our stuff and scoffed. Like he knew those wouldn't work."

"Hmmm." Maryse thought. "I should probably tell the Clave about these new vampires. Tell me again, how did the mundanes kill them."

"They beheaded them." Alec said, bemused. "Their blades seemed to burn the vampires."

"And ours didn't work?" Clary asked. "What if we face another vampire like this again?"

"I propose we find the mundies and force them to tell us how they did it?" Alec said.

"Sure Alec." Jace said sarcastically. "Lets go hunt down the two mundies that could beat something that we couldn't. We need a plan."

"First let's find out who they are." Maryse said expectedly.

"There was a really tall one," Alec started.

"Looked kind of like a moose." Jace snorted.

"And the other guy called him Sam." Alec continued, effectively ignoring Jace. "They were wearing a lot of layers of plaid. The shorter one had light brown hair while the other one had dark, almost black hair."

"So they must have checked into a motel right? Cause they probably don't live here. Alec, check motels in town and see if they have two guests registered with one named Sam." Clary suggested.

"There is a church," Castiel popped up while Sam and Dean were researching Nephilim, nearly giving them both a heart attack. "It appears to be hidden from onlookers but I can see it. There are several more places like these throughout the city. A bar, a warehouse, a penthouse and others. The church seems to be where the shadowhunters are rested."

"That's great Cas." Sam got up from his chair.

"I say we leave them be." Dean interrupted. "We survived this long without them, I doubt that the teenagers can help much. Let's leave them out of it."

"But Dean," Sam started but stopped at Dean's cold look.

"They do their thing and we do ours. There is no point mixing them up with us hunters. It'll only end up badly for them." Dean argued. "And I found us a new case here. A werewolf." Dean tossed a news article towards Sam.

"If that's all, I would like to return to heaven." Castiel disappeared before any of the brothers could give an answer.

"Come on." Dean said, packing a few things they would need to hunt down the monster. "It's nested at the corner of a park."

"Rogue werewolf." Luke said to Clary. "See if you can pass that on to Maryse. He used to be the strongest one in our pack so tell whoever she sends to be careful."

"May I take your order?" The waitress interrupted the pair and wrote down the order.

"Kylo Harve." Luke said. "That's his name."

"Do you know where he might be?" Clary asked.

"Let me write his address down, he should be in that proximity." Luke said. "Now enough Shadowhunters talk, how's everything going?"

A few tables over, Sam and Dean perked up at the words shadowhunters and werewolf.

"Did you hear that?" Sam asked.

"Rogue werewolf." Dean quoted as an affirmation. The duo sat in silence for a few minutes, trying to listen in to the table a few feet away.

"Look Dean, maybe we shouldn't go after this thing. It looks like they got this covered." Sam said.

"Nuh uh." Dean took a big bite of his burger. "Didn't you hear what he said? That werewolf's a fighter. We can't trust a bunch of kids to kill it. We should go after that thing tonight."

"But Dean. They seem to know more about this. Maybe…" Sam stopped his argument upon noticing that Dean wasn't listening.

Sam groaned. What did Dean have against the Nephilim. But Sam already knew. It was because of the Shadowhunters had helped them, there would have been a lot less casualties. A lot less innocent people would have died.

Hopefully the Winchester's would get to meet the Shadowhunters. Maybe then they could sort things out. But only if Sam knew what he was wishing for.


End file.
